16-year-old student Moira McKendry, gifted, popular and fun-loving, is found dead after a school party. The fatal head injuries indicate a violent crime. Moira's best friend, the introverted Hanna, was apparently the last person to see Moira alive. But Hanna can't remember anymore.

When estranged siblings Lindsay and Brad travel to Scotland at Christmas to reunite with their mother Jo, a big family secret is revealed.